The present invention relates generally to damping spacers for overhead conductor bundles, and particularly to an inertial weight means that is effective to dampen the vibration of two conductor bundles that tend to vibrate in phase.
In U.S. Pat. No. 3,940,553, issued in the name of the present inventor, Ronald G. Hawkins, the arms of a frameless damping spacer have hub structures that contain two elastomer damping elements. With relative rotational motion of the arms about the axis of a central pin securing the arms and damping elements together, the damping elements are effective to dampen the energy of the motion. However, relative vertical motion of the arms of the spacer, with a vertical arm connected to a lowermost conductor of a three-conductor bundle, is limited by the pin, the pin directly engaging the hub structure of each arm. Similarly, for the same reason, relative elliptical motion of the arms about the axis of the pin is not permitted.
However, as discussed in the text of the Hawkins patent, the structure disclosed therein has a number of significant advantages over damping spacers previous to the patent.
In U.S. Pat. No. 3,613,104 to Bradshaw, a frame-type damping spacer is shown in which the arm of a conductor clamp is provided with an opening 42 that accommodates a rubber sleeve 44. The arm and sleeve are then located and secured between two torsion discs located in hub portions of a frame member. The arm and frame members are provided with stop means 50, 51 and 52 to protect the sleeve and discs from excessive conductor motion. It will be noted that damping is again effected by rotational or torsional stresses imposed on the discs; other motions are limited by the direct mechanical connection of the frame and securing pin (FIG. 5) and by the sleeve between the clamp arm and pin; no travel space is provided between the arm and frame except that afforded by the discs and sleeve.